NEW YORK, NY - DECEMBER 20: Brother of convicted Ponzi king Bernard Madoff ,67-year-old Peter Madoff, arrives at U.S. District Court in Manhattan on December 20, 2012 in New York City. A plea agreement makes a 10-year prison term all but certain for Madoff who was convicted after he pleaded guilty to conspiracy and falsifying books and records of an investment adviser. (Photo by Spencer Platt/Getty Images)

Photo: Spencer Platt, Getty Images

NEW YORK, NY - DECEMBER 20: Brother of convicted Ponzi king Bernard...

The brother of imprisoned financier Bernard Madoff was sentenced Thursday to 10 years in prison for crimes committed in the shadow of his notorious sibling by a judge who said she disbelieved his claims that he did not know about the epic fraud.

Peter Madoff, 67, had agreed when he pleaded guilty in June to serve the maximum sentence allowable to the charges of conspiracy and falsifying the books and records of an investment adviser.

He follows to prison his 74-year-old brother, who is serving a 150-year sentence after admitting he created a fraud so large decades ago that thousands of people lost $20 billion.

U.S. District Judge Laura Taylor Swain urged Peter Madoff to tell the truth about what he knows about the fraud that cost thousands of investors their original $20 billion investment.

The judge said Peter Madoff was "frankly not believable" when he claimed at his plea that he learned of the fraud only when his brother revealed it to him before he surrendered.

"I am deeply ashamed of my conduct and have tried to atone by pleading guilty and have agreed to forfeit all of my present and future assets," Peter Madoff said.